How To Repair Damage Be Repair In Propeller Deicer Boot

Construction and Installation of Deice Boots

Deicer boots are fabricated of soft, pliable rubber, or rubberized fabric, and contain tubular air cells. The outer ply of the deicer boot is of conductive neoprene to provide resistance to deterioration by the elements and many chemicals. The neoprene likewise provides a conductive surface to dissipate static electricity charges. These charges, if immune to accumulate, would eventually belch through the boot to the metal peel below, causing static interference with the radio equipment. [Figure ane]

Figure 1. Deicing boots inflated (left) and deflated (right)

On modern aircraft, the deicer boots are bonded with an adhesive to the leading edge of fly and tail surfaces. The trailing edges of this type boot are tapered to provide a smoothen airfoil. Elimination of fairing strips, screws, and rivnuts used on older types of deicing boots reduces the weight of the deice organization. The deicer boot air cells are connected to system pressure and vacuum lines by non-kinking flexible hose.

When gluing the deice boots to the leading edge of wings and stabilizers, the manufacturer's instruction must be strictly followed. The glue is typically a contact cement unremarkably spread on both the airfoil and the boot and allowed to become tacky before mating the surfaces. Clean, paint-free surfaces are required for the glue to adhere properly. Removal of sometime boots is performed by re-softening the cement with solvent.

Inspection, Maintenance, and Troubleshooting of Rubber Deicer Kicking Systems

Maintenance on pneumatic deicing systems varies with each aircraft model. The instructions of the airframe or system components manufacturer should be followed in all cases. Depending on the aircraft, maintenance usually consists of operational checks, adjustments, troubleshooting, and inspection.

Operational Checks

An operational check of the system can be fabricated by operating the aircraft engines or by using an external source of air. Most systems are designed with a exam plug to allow basis checking the system without operating the engines. When using an external air source, make certain that the air pressure level does not exceed the test force per unit area established for the system. Before turning the deicing organisation on, notice the vacuumoperated instruments. If whatsoever of the gauges begin to operate, it is an indication that one or more check valves have failed to close and that reverse menstruum through the instruments is occurring. Right the difficulty before continuing the examination. If no movement of the musical instrument pointers occurs, plow on the deicing system. With the deicer organisation controls in their proper positions, check the suction and pressure level gauges for proper indications. The pressure judge fluctuates equally the deicer tubes inflate and debunk. A relatively steady reading should be maintained on the vacuum guess. Information technology should be noted that non all systems use a vacuum gauge. If the operating pressure and vacuum are satisfactory, observe the deicers for actuation. With an observer stationed outside the aircraft, check the inflation sequence to be sure that it agrees with the sequence indicated in the aircraft maintenance manual. Check the timing of the system through several consummate cycles. If the bicycle time varies more than than is allowable, determine the difficulty and correct it. Inflation of the deicers must exist rapid to provide efficient deicing. Deflation of the boot being observed should exist completed before the adjacent aggrandizement cycle. [Figure 2]

Figure ii. Test equipment used to test a wing deice system (left), and test equipment installed in the shipping for testing (right)

Adjustments

Examples of adjustments that may exist required include adjusting the deicing arrangement control cablevision linkages, adjusting arrangement pressure relief valves, and deicing arrangement vacuum (suction) relief valves. A pressure relief valve acts as a safety device to relieve excess force per unit area in the event of regulator valve failure. To adjust this valve, operate the aircraft engines and conform a screw on the valve until the deicing pressure gauge indicates the specified force per unit area at which the valve should relieve. Vacuum relief valves are installed in a organisation that uses a vacuum pump to maintain constant suction during varying vacuum pump speeds. To adjust a vacuum relief valve, operate the engines. While watching the vacuum (suction) judge, an assistant should adapt the suction relief valve adjusting screw to obtain the correct suction specified for the system.

Troubleshooting

Not all troubles that occur in a deicer organisation can be corrected by adjusting arrangement components. Some troubles must exist corrected by repair or replacement of system components or by tightening loose connections. Several troubles common to pneumatic deicing systems are shown in the left-hand column of the chart in Effigy 3. Notation the probable causes and the remedy of each trouble listed in the nautical chart. In addition to using troubleshooting charts, operational checks are sometimes necessary to determine the possible cause of problem.

Figure 3. Troubleshooting guide for wing deice organisation

Inspection

During each preflight and scheduled inspection, check the deicer boots for cuts, tears, deterioration, punctures, and security; during periodic inspections, go a footling further and check deicer components and lines for cracks. If atmospheric condition bang-up of rubber is noted, apply a coating of conductive cement. The cement, in addition to sealing the boots against weather, dissipates static electricity so that information technology does not puncture the boots by arcing to the metal surfaces.

Deice Boot Maintenance

The life of the deicers tin can exist greatly extended past storing them when they are not needed and by observing these rules when they are in service:

1. Practice not drag gasoline hoses over the deicers.
2. Proceed deicers costless of gasoline, oil, grease, dirt, and other deteriorating substances.
3. Do non lay tools on or lean maintenance equipment confronting the deicers.
4. Promptly repair or resurface the deicers when chafe or deterioration is noted.
5. Wrap deice boots in newspaper or sail when storing.

Thus far, preventive maintenance has been discussed. The actual work on the deicers consists of cleaning, resurfacing, and repairing. Cleaning should normally be done at the same time the aircraft is washed, using a mild soap and h2o solution. Grease and oil tin be removed with a cleaning amanuensis, such every bit naptha, followed by lather and h2o scrubbing. Whenever the caste of clothing is such that it indicates that the conductivity of the deicer surface has been destroyed, information technology may be necessary to resurface the deicer. The resurfacing substance is a black, conductive neoprene cement. Prior to applying the resurfacing cloth, the deicer must be cleaned thoroughly and the surface roughened. Cold patch repairs can be fabricated on a damaged deicer. The deicer must exist relieved of its installed tension before applying the patch. The area to exist patched must be clean and buffed to roughen the surface slightly. Patches are glued in identify. Follow manufacturer's instructions for all repairs.

Electric Deice Boots

A few modern aircraft are equipped with electric deice boots on fly sections or on the horizontal stabilizer. These boots incorporate electric heating elements which are bonded to the leading edges similarly to pneumatic deice boots. When activated, the boots oestrus upwardly and melt the water ice off of leading edge surfaces. The elements are controlled by a sequence timer in a deice controller. Water ice detector and ram air temperature probe inputs initiate operation when other flying condition parameters exist. The kick elements turn ON and OFF in paired sections to avert aerodynamic imbalance. The system is inoperative while the aircraft is on the ground. Figure 4 illustrated such a system. A benefit of electrical deice boots is the conservation of engine bleed air. Current draw is express to just those periods when de-ice is required.

Effigy iv. Electric stabilizer deice system

RELATED POSTS

• Fly and Horizontal and Vertical Stabilizer Anti-Icing Systems
• Wing and Stabilizer Deicing Systems
• Wing and Stabilizer Deicing Systems Components
• Propeller Deice Organisation
• Ground Deicing of Aircraft
• Rain Command Systems

Source: https://www.aircraftsystemstech.com/2017/05/inspection-maintenance-and.html

Posted by: mooresblaway.blogspot.com

Share this post